Asymmetric Hard Domain-Induced Robust Resilient Biocompatible Self-Healable Waterborne Polyurethane for Biomedical Applications

The synthesis of eco-friendly and biocompatible waterbornepolyurethanes(WPUs) through judicious molecular engineering with supreme mechanicalstrength, good shape recoverability, and high self-healing efficiencyis still a formidable challenge because of some mutually exclusiveconflicts among these properties. Herein, we report a facile methodto develop a transparent (80.57-91.48%), self-healable (efficiency67-76%) WPU elastomer (strain 3297-6356%) with the highestreported mechanical toughness (436.1 MJ m(-3)), ultrahighfracture energy (126.54 kJ m(-2)), and good shaperecovery (95% within 40 s at 70 & DEG;C in water). These results wereaccomplished by introducing high-density hindered urea-based hydrogenbonds, an asymmetric alicyclic architecture (isophorone diisocyanate-isophoronediamine), and the glycerol ester of citric acid (a bio-based internalemulsifier) into the hard domains of the WPU. Most importantly, plateletadhesion activity, lactate dehydrogenase activity, and erythrocyteor red blood corpuscle lysis demonstrated the hemocompatibility ofthe developed elastomer. Simultaneously, the cellular viability (live/dead)assay and the cell proliferation (Alamar blue) assay of human dermalfibroblasts corroborated the biocompatibility under in vitro conditions.Furthermore, the synthesized WPUs showed melt re-processability withretention of mechanical strength (86.94%) and microbe-assisted biodegradation.The overall results, therefore, indicate that the developed WPU elastomermight be used as a potential smart biomaterial and coating for biomedicaldevices.